This invention relates to an air conditioning terminal, and in particular, to an arrangement of parts whereby undesirable noise generation is prevented.
The utilization of air conditioning terminals to supply conditioned air from a central source thereof to offices, school rooms, and other similar spaces in multi-room buildings has become increasingly prevalent. Such terminals are typically located in the ceiling of the rooms being conditioned, or on the floor thereof adjacent the windows. The use of such terminals in rooms that are normally occupied by people dictates that the conditioned air be discharged from the terminals as quietly as possible. That is to say, noise generated by operation of the terminals should be maintained at a minimum.
An air conditioning terminal of the type suitable for installation in the ceiling that has met with widespread commercial success is disclosed in U.S. Pat. No. 3,554,111, issued Jan. 12, 1971 and assigned to the same assignee as the assignee hereof.
The terminal disclosed in the aforecited patent includes an assembly for regulating the quantity of conditioned air discharged into the room or space being conditioned in accordance with the actual temperature requirements of the occupants thereof. Such air regulating assembly includes an inflatable bellows, the amount the bellows is inflated varying inversely with the quantity of conditioned air discharged from the terminal.
The conditioned air is supplied to each of the terminals from a central station refrigeration machine via suitable ducts. The terminals include a plenum section in communication with a supply duct. The terminals further include a distribution chamber having the air regulating assembly disposed therein. A plate, having a plurality of openings, is interposed between the plenum section and the distribution chamber.
In newer terminals, it has been deemed desirable to increase the quantity of conditioned air discharged therefrom to meet the requirements of certain applications. It has been necessary to provide a second air regulating assembly in the newer terminals of the type described to accommodate the increased quantity of air flowing through the unit. The second assembly defines an air flow path parallel to the flow path defined by the first assembly. The air passing through the opening regulated by the inflatable bellows undergoes a drop in pressure. It is believed the pressure differential thus acting on the air regulating assemblies causes vibratory movement. When the terminals only contained one air regulating assembly, noise generated as a result of the vibratory movement was not noticeable.
The introduction of the second assembly intensifies any noise generated as a result of vibratory or relative movement of each assembly. It is believed that such intensified sound generation is caused by resonance between the two regulating assemblies.
Accordingly, any noise resulting from the vibratory movement of either of the assemblies will result in undesirable noise in the room or space being conditioned. It is therefore essential that vibratory movement of the assemblies be eliminated.